Compounds generally known as chlorosilanes are used as raw materials in polysilicon films, silicon nitride films, silicon oxide films, etc. that form integrated circuits in semiconductor devices and as raw materials for solar cells, liquid crystals, and silicon, and the like. From the viewpoint of industrial use, monosilanes, which are compounds conventionally formed by bonding a hydrogen or halogen atom to a silicon atom, are compounds representative of chlorosilanes and are produced and used on an industrial scale. Meanwhile, the progression of semiconductor device production technology can be said to have already reached its limits, but the progress of high integration has not halted, and for density to continue increasing, there is a need for raw materials which can form circuits at lower temperatures in order to suppress the spread of impurities caused by heating during the formation of integrated circuits. Under these conditions, the use of pentachlorodisilane, which can form circuits at lower temperatures in comparison with monosilanes such as monosilane and dichlorosilane, as well as the use of hexachlorodisilane, which is a similar compound, as raw materials has gathered attention and development of integrated circuits using these compounds is on the rise.
Thus far, methods for producing pentachlorodisilane have not been disclosed, but Patent Document 1 indicates that pentachlorodisilane is included in the exhaust gas of a Siemens method to obtain high-purity polycrystalline silicon as a reaction including pentachlorodisilane as a product, that is, pentachlorodisilane is included in the exhaust gas after introducing trichlorosilane and hydrogen to a silicon generating reactor and reacting the two. Further, Patent Document 2 discloses pentachlorodisilane existing in the off gas when precipitating polycrystalline silicon from chlorosilane and hydrogen. Furthermore, Patent Document 3 also discloses that, in addition to silicon tetrachloride and hexachlorodisilane, pentachlorodisilane, octacholorotrisilane, etc. are included in high-boiling chlorosilane-containing compounds generated in a polycrystalline silicon production process.    Patent Document 1 JP 2006-169012 A    Patent Document 2 JP 2009-528253 A    Patent Document 3 JP 2009-227577 A